Refactor renderer-side script injection

extensions/common/extension_messages.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // IPC messages for extensions.
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 #include <vector>
 
@@ skipping 565 matching lines @@
 // Sent from the renderer to the browser to notify that content scripts are
 // running in the renderer that the IPC originated from.
 // Note that the page_id is for the parent (or more accurately the topmost)
 // frame (e.g. if executing in an iframe this is the page ID of the parent,
 // unless the parent is an iframe... etc).
 IPC_MESSAGE_ROUTED3(ExtensionHostMsg_ContentScriptsExecuting,
                     ExecutingScriptsMap,
                     int32 /* page_id of the _topmost_ frame */,
                     GURL /* url of the _topmost_ frame */)
 
-// Sent from the renderer to the browser to request permission for a content
-// script to execute on a given page.
+// Sent from the renderer to the browser to request permission for a script
+// injection.
 // If request id is -1, this signals that the request has already ran, and this
 // merely serves as a notification. This happens when the feature to disable
 // scripts running without user consent is not enabled.
-IPC_MESSAGE_ROUTED3(ExtensionHostMsg_RequestContentScriptPermission,
+IPC_MESSAGE_ROUTED3(ExtensionHostMsg_RequestScriptInjectionPermission,
                     std::string /* extension id */,
                     int /* page id */,
                     int /* request id */)
 
 // Sent from the browser to the renderer in reply to a
-// RequestContentScriptPermission message, granting permission for a content
+// RequestScriptInjectionPermission message, granting permission for a script
 // script to run.
-IPC_MESSAGE_ROUTED1(ExtensionMsg_GrantContentScriptPermission,
-                    int /* request id */)
+IPC_MESSAGE_ROUTED1(ExtensionMsg_PermitScriptInjection, int /* request id */)
 
 // Sent by the renderer when a web page is checking if its app is installed.
 IPC_MESSAGE_ROUTED3(ExtensionHostMsg_GetAppInstallState,
                     GURL /* requestor_url */,
                     int32 /* return_route_id */,
                     int32 /* callback_id */)
 
 // Optional Ack message sent to the browser to notify that the response to a
 // function has been processed.
 IPC_MESSAGE_ROUTED1(ExtensionHostMsg_ResponseAck,
@@ skipping 51 matching lines @@
 //   FrameHostMsg_DidCommitProvisionalLoad. Currently this only fires for the
 //   main frame.
 // * Something changed on an existing frame causing the set of matching searches
 //   to change.
 IPC_MESSAGE_ROUTED1(ExtensionHostMsg_OnWatchedPageChange,
                     std::vector<std::string> /* Matching CSS selectors */)
 
 // Sent by the renderer when it has received a Blob handle from the browser.
 IPC_MESSAGE_CONTROL1(ExtensionHostMsg_TransferBlobsAck,
                      std::vector<std::string> /* blob_uuids */)